1. Field of the Invention
The present invention relates to a process for producing a lead-acid battery and more particularly, a process for producing a lead-acid battery related to welding of terminal portions of the battery, and a jig for producing the same.
2. Description of the Related Art
It is a conventional practice either to produce a lead-acid battery of a so-called bushing terminal type in which a lead bushing also serves as a terminal, by inserting an upper portion of a pole protruding upwards from a cell chamber within a battery container of an assembled lead-acid battery through an insertion hole in a lead bushing cast in a lid made of a synthetic resin by a cast molding process, and welding the pole inserted and the lead bushing around an outer periphery of the pole to each other, or to produce a lead-acid battery of a type having a terminal member led out sideways by mounting a separately fabricated terminal on an outer peripheral surface of a lead bushing, and welding the bushing and the terminal to each other using a burner.
In this case, at the time of welding using the burner, as mentioned above, in order to previously prevent deformation of the lid as a result of welding heat, whereby an air-tightness failure would occur between the lid and the lead bushing integrally cast in the lid, it has preferably been practiced in general to carry out the burner welding in such a state that an annular mold of a jacket type for passing cooling water therethrough is disposed in contact with the peripheral surface of the lead bushing or the peripheral surface of the terminal mounted on the bushing.
More particularly, in the case of producing the lead-acid battery of a bushing terminal type as described above, it has been conventional practice to weld terminal portions to be welded of the lead-acid battery, i.e., mutually abutted or adjacent peripheral portions of the lead bushing integrally cast in a lid made of a synthetic resin by an insertion molding and a pole of a battery body inserted through a cylindrical hole in the lead bushing to each other by a burner flame.
In the case of welding of the pole and the lead bushing using the burner, however, if the height from the surface of the lid to an upper end surface of the lead bushing is not more than 8˜10 mm, in other words, is less than 8˜10 mm, deformation of the lid is unavoidable as a result of the heat generated during the burner-welding, even if the above-mentioned cooling means is used, an air-tightness failure occurs between the lid and the lead bushing formed in the lid. Therefore, it is required that the upper end of the lead bushing protrudes more than 8˜10 mm from the surface of the lid, and hence, such a corresponding height-wise space enough to accommodate the lead bushing terminal is required above the upper surface of the lid. On the other hand, it is desirable to produce a lead-acid battery of the type leading out the terminal sideways which is capable of lowering a height-wise space above the upper surface of the lid. However, in the burner-welding of a base portion of the lead bushing and a plate-shaped terminal having a thickness of several mm, fitted thereon the distance between the portion of the terminal to be welded and the surface of the lid is only several mm, so that an air-tightness failure is often generated between the lid and the lead bushing cast in the lid due to the thermal deformation of the lid caused by the burner-welding, to result in many manufacture losses.
Therefore, it is desired to remove such inconveniences and develop a process for producing a lead-acid battery, wherein welding of the required portions can be achieved smoothly without any manufacture loss.
When welding of the foregoing terminal portions is carried out using a burner flame, the lid made of a synthetic resin around the terminal portion is softened by heat of the burner flame to create a gap between the lid and the bushing, thereby bringing about an air-tightness failure. In addition, it is difficult to make a depth of penetration of the welded portions uniform and further, the appearance shape of the welded terminal portion is collapsed and hence, it is difficult to make a welded terminal of a definite shape.
Accordingly, it is desired to remove such inconveniences and develop a process for producing a lead-acid battery by such a process for welding of the terminal portions that is capable of welding the terminal portions to each other stably and satisfactorily without any manufacture loss.